New technology has been reported for the synthesis of olefins from methanol. (Chemical Engineering, January 1996, page 17). As described in the literature, this process converts methanol in a fluidized-bed reactor at a pressure between 1 and 5 atmospheres and a temperature in the range of 350° C. to 500° C. A zeolite-type of catalyst consisting of silicon-aluminum-phosphorous oxide is used to promote the reaction.
The process is capable of converting at best about 80 percent of the methanol to ethylene and propylene in varying proportions of these olefins. The reaction is exothermic and therefore the heat of reaction must be removed by suitable means. Although this process promises to free manufacturers from reliance on traditional feedstocks, e.g., naphtha, it nevertheless is tied to the economics of methanol.
Notwithstanding interest expressed in this new technology for producing olefins from methanol, there is some concern about its limitations. Therefore it is an object of the present invention to offer an improved method for the manufacture of olefins. This object as well as other features and advantages will be apparent from the following description and the FIGURE which is included.